Promise.race()

The Promise.race() method takes an iterable of promises as input and returns a single Promise. This returned promise settles with the eventual state of the first promise that settles.

Syntax

Promise.race(iterable)

Parameters

• iterable
  • : An iterable (such as an Array) of promises.

Return value

A Promise that asynchronously settles with the eventual state of the first promise in the iterable to settle. In other words, it fulfills if the first promise to settle is fulfilled, and rejects if the first promise to settle is rejected. The returned promise remains pending forever if the iterable passed is empty. If the iterable passed is non-empty but contains no pending promises, the returned promise is still asynchronously (instead of synchronously) settled.

Description

The Promise.race() method is one of the promise concurrency methods. It's useful when you want the first async task to complete, but do not care about its eventual state (i.e. it can either succeed or fail).

If the iterable contains one or more non-promise values and/or an already settled promise, then Promise.race() will settle to the first of these values found in the iterable.